applied changes made by Luis Pabon to support gluster-swift

The current changes support only one account per volume
The next changes will be made to add support for multiple accounts
Also modified unit tests that were failing after code changes.
Original changes were made here: https://github.com/lpabon/swauth/tree/gluster-swift

Change-Id: I5577d7dc042fc22de8625c8bdf30329cc3338cb9
Signed-off-by: Thiago da Silva <thiago@redhat.com>
Reviewed-on: http://review.gluster.org/6107
Reviewed-by: Luis Pabon <lpabon@redhat.com>
Tested-by: Luis Pabon <lpabon@redhat.com>